Washington
— Among the 45 senators who questioned the top US military and diplomatic officials in Iraq in Congress this week, perhaps none had more at stake than the five who are running for president.

It may be one of them, after all, who inherits the substantial US troop presence in Iraq that President Bush apparently intends to leave for his successor. And so, at times, the hearings were as much a campaign event as a signal moment in Mr. Bush's long struggle to turn Iraq into a "beacon of liberty in the Middle East," as he has put it.

The sound bites served up for possible campaign ads weren't hard to miss: "This continues to be a disastrous foreign-policy mistake," said Sen. Barack Obama (D) of Illinois, who used up most of his seven minutes with his own remarks rather than questions.

"I will do everything in my power to see that our commanders in Iraq have the time and support they request to win this war," said Sen. John McCain of Arizona, the only Republican among the five senator-candidates and the Republican candidate most closely aligned with Bush's Iraq policy.

The long-awaited appearance on Capitol Hill by Gen. David Petraeus and Ambassdor Ryan Crocker had the immediate effect of sending all the presidential candidates into their parties' ideological corners, where all but one of the Republican hopefuls supports Bush on Iraq and all the Democrats oppose him.

Just last week, during a campaign appearance in New Hampshire, former Massachusetts Gov. Mitt Romney (R) called the Iraq war a "mess," while this week he is putting out press releases that say the surge is working.

Perhaps the candidate who gained the most this week is Senator McCain, whose once-high-flying campaign went into free fall earlier this summer and is now starting to come back. His hard-core support for the Iraq war has always squared with the views of the Republican base, but it has put him at odds with the independent voters who have voted Republican in the past and who gave him a resounding victory in the New Hampshire primary over George W. Bush in 2000.

In this week's hearings, where General Petraeus described both progress and challenges in Iraq, it was McCain's moment to remind voters that he had disagreed with the Bush administration's initial strategy in Iraq – sending in far fewer troops than McCain had hoped for – and to state that now "we're getting it right because we finally have in place a strategy that can succeed."

But even as the week's hearings enhanced political polarization – exacerbated by the antiwar Moveon.org's incendiary ad in The New York Times referring to "General Betray Us" – the intense focus on Iraq also highlighted the intraparty skirmishing among the candidates. Just as last week, McCain took on Mr. Romney over Iraq during a New Hampshire debate, this week it was the Democrats' turn to fire at one another and try to shake up the nomination race.

Senator Obama, who consistently places second to Clinton by a substantial margin in national polls, delivered his third major foreign-policy speech of the campaign. His latest plan for Iraq calls on the Bush administration to begin pulling out brigades immediately, at a rate of one or two a month, until the withdrawal is complete. The plan did not appear substantially different from his previous proposals, and elicited criticism from more hard-line Iraq war opponents also running for the Democratic nomination.

On Wednesday, Sen. Christopher Dodd (D) of Connecticut took a swipe at both Obama and Clinton: "I was disappointed that Senator Obama's thoughts on Iraq today didn't include a firm, enforceable deadline for redeployment, and dismayed that neither he nor Senator Clinton will give an unequivocal answer on whether they would support a measure if it didn't have such an enforceable deadline."

Senator Dodd's critique highlighted the fact that the top two Democratic hopefuls have been the most cautious in their prescriptions for Iraq. Another candidate, former Sen. John Edwards (D) of North Carolina, also sought to break through by purchasing TV time on MSNBC to deliver his own speech right after Bush's address to the nation.

Analysts are skeptical that any of this week's jockeying, while having the air of a watershed moment in the 4-1/2 year old war, will do much to alter either public opinion on the war or the shape of the presidential contest.

"I'm beginning to think that in many ways the American people are exhausted by this whole issue," says Leon Panetta, a member of the bipartisan Iraq Study Group and President Clinton's former chief of staff. "There are so many voices out there, and it's really tough to break through, particularly if you don't have an answer that's so unique that everybody says, 'oh my God, why didn't I think of that?' "

Mr. Panetta, who now runs a think tank in California, also regrets the Moveon ad as "over the line," adding that it put the Democrats on the defensive and gave the GOP a rallying point. "It pulls the Democrats to one side and makes it much more difficult to bring them along on any kind of alternative [Iraq strategy]," he says.